iPhone 4S pre-orders may have topped 500,000 in the U.S. before Apple ran out

If you had any doubts that Apple AAPL would be able to beat the record 1.7 million iPhones sold in three days in June 2010, you can put them to rest.

Despite early glitches that slowed down pre-orders, AT&T T announced Friday it had taken orders for 200,000 iPhone 4S units in the first 12 hours — “the most successful iPhone launch we’ve ever had.” iPhone 4 pre-orders last year were 10 times greater than the iPhone 3GS’s, and that was when AT&T was the iPhone’s only U.S. carrier.

This year Apple is offering pre-orders to three carriers in the U.S.: AT&T, with 98.6 million wireless customers, Verizon VZ with 106.3 million and Sprint S with 52 million. Given the pent-up demand at Verizon and Sprint, it’s not much of a stretch to assume that Verizon also pre-sold at least 200,000 and Sprint, with half the customer base, another 100,000. That’s a total of half a million units in the U.S. alone.

Apple announced on June 16, 2010 that had taken pre-orders for 600,000 iPhone 4 units, but that was after 24 hours, and that number included orders placed with its overseas carriers.

Last year, Apple offered pre-orders in five countries: US, France, Germany, Japan and the U.K. This year it added Australia and Canada to the mix. Six of those countries had run out of iPhones for pre-order by 6:55 a.m. PST Friday. The U.S. ran out 12 hours later.

The fact that the iPhone 4S uses the same form factor as the iPhone 4 makes it more likely that the company will be able to keep up with demand this year in what will be its most aggressive rollout yet.

Two weeks after the Oct. 14 launch, the iPhone 4S will go on sale in 22 more countries, including Austria, Belgium, Denmark, Finland, Ireland, Italy, Latvia, Liechtenstein, Luxembourg, Mexico, the Netherlands, Norway, Slovakia, Spain, Sweden, and Switzerland. Last year it was five weeks after the June 24 launch before Apple expanded the iPhone 4 rollout, and then to only 17 more countries.

In June 2010, Apple had 154 carrier partners. By June 2011, it had 228. Tim Cook didn’t say on Tuesday how many it has now. We’ll almost certainly find out on Oct. 18, when Apple releases its quarterly earnings for the fiscal year that ended two weeks ago.